ML19343C208

LER 76-021/03L-0:on 760820,while Performing Pump Operability Test for Containment Spray Sys 1,valve V-21-18 Failed to Open When Auto Start Signal Applied.Caused by Contact Switch Failure Due to Dirty Switch Contacts

ML19343C208
Person / Time
Site:	Oyster Creek
Issue date:	09/02/1976
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
LER-76-021-03L, LER-76-21-3L, NUDOCS 8103020111
Download: ML19343C208 (3)

Text

,

LICENSEE EVENT REPOR" CDP TROL BLOCK:l l l l l l l [PLEATE CCINT ALL RElulREJ INF2RM ATiof 1 6 TV E iAME LCENSE NUMBER E

% lNlJl0lClPl1l 14 l0l0l-l0l0l0l0l0l-l0l0l 15 25 l 4 l 1 l 1l 1l 1l 26 30 l0 l 3 l 31 32 7 89 DOCKET NUVDER EVENT DATE REPORT OATE CATECORY T7P S QCOtrT l57 l l W M l0 l 5l 0l-l 0l 2l1l 9l l0 l8 l2 l0 l7 l6 l l0 l9 l0 l 2l 7l C 60 68 69 74 75 E 7 8 50 59 61 EVENT DESCRIPTION EG l While performing the monthly pump operability test for Containment Spray System I, E

7 89 Maintenance

@@ l valve V-21-18 failed to open when an auto start signal was applied.

7 89 EE l personnel traced the failure to a defective interlock switch in the valve moto 7 89

@ l The switch was replaced and the test was completed. (50-219/76-21-3L) g 7 89

$1 7 89 pmE E

R R VOLATON DE OOE COMPONENT CODE

'M lSl Bl d l Cl Kl TlB l R l Kl W 43 l Gl 0l 8l 0l 44 47

@ 48 7 89 10 11 12 17 '

CAUSE DESCn:PTION

@ l A General Electric, Model No. CR105X, auxiliary contact switch failed to operate.

7 89 The switch was

@ l The cause of the failure was attributed to dirty switch contacts.

7 09 1 l immediate1v replaced.

OTHER STATUS bSCOERY DtSCOVERY DESCR* TON STA S  % POWER l0l9l6l12 13l d45 l During inonthly pump test.

7 8 9 b 10 N/A l 44 46 E RELEASE LE SED AMOUNT OF ACTMTY LOCATON N 7A 7 8 9 d OF WREL ASE l 10 11 N/A l 44 l

45 L PERSONNEL EXPOSURES NUMBER TYFE DESCR;PTON N/A DE l0 10 l0 l [ Z_l [ '

E 7 89 11 12 13 ,

PERSONNEL INJUR ES NWBER DESCAPTON N/A

$ l0 l0 l0 11 7 89 l 12l .

l Probable Consequences N/A EE l L 7 89 LOSS OR DAMAGE TO FACILITY DESCAroTON 1YPE FA t

l 7 89 10 PUBLICITY N/A b! t ADOITIONAL FACTORS l 7 89 8

0

$~ ll

@6Mdol/ /NAME- U""ld ^*

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088l,M nager WONE: ,,, ,,,,,,

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-OYSTER CREEK NUCLEAR GENERATING STATION:

Forked' River, New Jersey 08731" ,

Licensee Event Report- _ -

Reportable Occurrence No. ~ 50-219/76-21-3L : ,,

, Report Date

. September 2, 1976

~0ccurrence Date August 20, 1976 -

Identification of Occurrence

~

- Failure of containment spray system I; torus spray valve V-21-18-to function when called upon_to do so. This event is considered to be a 30-day reportable occurrence as defined 'in the Technical Specifications, -paragraph 6.9.2.b.2.

Conditions Prior to Occurrence lhe-major plant parameters at the time of the occurrence were as follows:-

Power: . Reactor, 1874 MWt ,

Generator, 642 MWe - (g) ,.

6 Flow: Recirculation, 60.0 x 10 . lb/hr Feedwater, 6.99 x 10 6 lb/hr Stack Gas: 14,500 pci/sec Description of-Occurrence ,

On August 20, 1976, while performing the monthly pump operability test for containment spray system 1, which was done in conjunction with the automatic actuation test, it was observed that valve V-21-18 failed to open when a containment spray auto start signal was applied. Normally, the valve opens to admit a flow of cooled water from the-discharge of the containment spray. system-  ;

back into the torus via a spray header in the torus vapor space. . Electrical.

maintenance personnel traced the cause of the f ailure to a defective interlock' .

switch 11. the valve motor control center. .Following switch replacement, the-auto actuation test for containment spray system I was completed _ satisfactorily.

Apparent Cause of Occurrence The valve motor control logic is interlocked such that- it is not possible to ,

simultaneously apply both an open and close signal to the valve. The inter-f lock feature is accomplished by using two auxiliary ' switches, one which  ;

operates with the motor closed" contactor to open the control power circuit to the motor opened" contactor, and one which operates with the " motor opened".

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Abnormal Occurrence No. 50-219/76-21-3L September 2, 1976 Page 2 contactor to open the control power to the " motor closed" contactor. The

" motor closed" auxiliary switch failed with its contacts open, thus preventing the motor open contactor from closing when called upon to do so. This in turn, prevented the valve from opening. (Reference Drawing GE 157B6350, Sheet 167, Zone K-10). The auxiliary switch is a sliding switch with a spring return to normal (closed contacts). Failure was attributed to dirty switch contacts.

Analysis of Occurrence The failure of valve V-21-18 to function is considered to be of minimial signif-icance since system II torus spray valve V-21-15 functioned satisfactorily.

The torus spray which is approximately 150 gpm for each loop is intended to cool the gases which are contained in the torus vapor space under loss of coolant accident conditions. Failure of this valve to operate resulted in a loss of system redundancy.

Corrective Action The auxiliary switch was replaced and the system was satisfactorily tested.

No additional corrective action is contemplated.

Failure Data Manufacturer: General Electric

• Type: Auxiliary Contact Model Number: CR105X l

e wa P00R ORIGINAL l

.